Lysosomes and lysosomal enzymes have been implicated in development of neoplasia and in tumor invasiveness. Particularly noteworthy is the altered subcellular localization and chromatographic properties of several acid hydrolases in neoplastic tissue. While the mechanism by which lysosomes form is unknown, recent experiments suggest an extracellular intermediate may be involved in the packaging of newly formed enzyme. Several forms of Beta-glucuronidase have been isolated from rat tissues by a novel antibody-Sepharose method. Most of these forms, when injected into the anesthetized rat, are cleared immediately. Other forms remain in the plasma. The latter are enhanced in plasma by administration of diisopropylfluorophosphate (DFP). The first objective of these studies is to elucidate the mechanism of DFP enhanced hyper-Beta-glucuronidemia. The second objective is to resolve the mechanism by which Beta-glucuronidase is cleared from the plasma, presumably by liver, and to proceed with biosynthetic experiments to follow movement of newly formed enzyme. The third objective is to investigate the multiplicity and subcellular distribution of lysosomal enzymes in normal and virus transformed rat embryo fibroblasts.